Electromagnetic oscillating-armature piston pump



Aug. 23, 1966 L. UNGER 3,267,355

ELECTROMAGNETIC OS CILLATING-ARMATURE PISTON PUMP Filed Aug. 25, 1964 2Sheets-Sheet l INVhNTOR.

LADISLAUS UNGLR.

ATTOIX LLIL Aug. 23, 1966 L.. UNGER 3,267,366

ELECTROMAGNETIC OSCILLATING-ARMATURE PISTON PUMP Filed Aug. 25, 1964 2Sheets-Sheet 2.

FIG.2

INVENIOR.

LADIS LA US UNGILH.

ATTOhNLY.

United States Patent 3,267,866 ELECTRUMAGNETKC USCILLATENG-ARMATUREPISTON PUMP Ladislaus Unger, Malsch, Kreis Karlsruhe, Germany, assignorto Otto Eckerle Filed Aug. 25, 1964, Ser. No. 392,012 12 Claims. (Cl.10353) Yet another object is to provide a pump wherein the return springoperates for the dual purpose of returning the piston in retrogrademovement and, concurrently positively checking over-stroke to preventchatter, excessive noise, and to increase efiiciency.

Ancillary to the immediately foregoing object, it is a purpose toprovide a piston pump of the type aforesaid wherein clearance betweenthe piston and cylinder headv at the beginning of a working stroke canbe held at a minimum, thus increasing the expansion ratio, the possibleetfec-tive range of operating pressures, and reducing the overall sizeof the pump, for any given capacity.

A still further object is to provide a pump which, by reason of theconstruction features aforesaid, can be used as a vacuum pump.

Yet another object is to provide a pump which operates with smallelectric or hysteresis losses over a wide range of sizes and capacities.

Other objects and advantages of the invention will become clear to thoseskilled in the art, after a study of the following detailed descriptionin connection with the acc-ompanying drawing.

In the drawing:

FIGURE 1 is an axial section through a pump embodying the invention; and

FIGURE 2 is a corresponding section through a modification.

Referring in detail to FIGURE 1, a relatively heavy support 12 with anintegral central upward extension 14, has a housing 1 detachably securedto its under face, as by threads, not shown. The housing is shaped toaccommodate with a smooth fit the core 2 of an electromagnet. The coreis made up of a plurality of 'E-shaped laminations, it being noted thatthe central upward arm of the E is shorter than the right and left arms,as viewed upon the figure, to define a space 6. Winding 3 of theelectromagnet is wound on a spool which fits the projection 5 andextends across space 6. Housing 1 is of somewhat greater verticaldimension than that of the electromagnet, to leave aspace which isoccupied by a laminated yoke 4.

Housing '1, central arm 5 of core 2, yoke 4 and support 12 have centralaligned passages such as 7 in arm 5, to receive with a smooth lit thepump cylinder 8. It is noted that this cylinder has an enlargedcylindrical upper end threaded into a corresponding recess in the underside of support 12. The bore of the cylinder is reduced in diameterabout midway of its length to form a circular shoulder 8a, and again atits lower end to define a second circular shoulder 8b.

Piston 9, of magnetic material, has a smooth fit within cylinder 7, andis centrally bored to provide a passage .for fluid. The bore in piston 9has a counterbore 9a ice opening through its top end. The bore has athin metallic lining 9b which is headed over or flared at its top end tofit over the shoulder formed between the bore and counterbore. Thelining is unitarily fixed with the piston, as by a press fit orsweating. The lower end of the lining projects a short distance belowthe piston. This projec tion has a flanged collar 18 journaled forrotation thereon.

At its upper end the counterbore in piston 9 is enlarged to form ashoulder on which is fixed, as by press fit, or soldering, acentrally-apertured valve seat 11. A helical coil compression spring ispositioned within counterbore 9a and acts to urge disk valve 9d upwardlyagainst its seat 11.

The lower end of the central bore in cylinder -8 is fitted with a sleeve16 with central passageway 16a. The sleeve has a flange spaced slightly'below its upper end. This flange is sized 'for a smooth fit within thelower reduced portion of the cylinder. The lower end of the sleeve isthreaded as indicated at 17, to engage the threaded lower end ofcylinder *8 and thus enable the compression of an O-ring seal betweenthe shoulder 8b at the lower end of the cylinder and the shoulder formedby the flange 0f the sleeve. The projecting threaded end of the sleevealso provides a connection for an exhaust pipe, not shown.

Helical coil compression spring 10 is positively connected at its upperend with collar 18 and at its lower end with sleeve 16. The connectionsare conveniently effected by the formation of channels or coarse threadson the reduced collar and sleeve and which are threaded or forced intothe respective ends of the spring. The spring is so formed that in theposition shown upon the figure, it is substantially unstressed but, ofcourse, becomes compressed upon downward movement of piston 9. On theother hand, when the piston rises above the position shown, the springbecomes tensioned and thus acts to check motion of the piston intocontact with the suction valve above. of the piston is prevented fromoverstroke and striking the suction valve, at the end of the retrogradestroke. The clearance may be kept at a minimum so that the expansionratio may be relatively large.

The central bore in support 12 forms a short upward continuation of thesame diameter as the contiguous end of cylinder 8. The bore is thenreduced in diameter at 23 and finally expands into an internallythreaded connection for an inlet pipe, not shown, from a source of fluidto be pumped. The reduced portion of the bore is threaded to take ashort section of tubing or cage having a flange 22 seated against thedownwardly-facing shoulder formed by the upper end of the cylinder bore.The lower end of this tube forms a downwardly-facing seat for a disksuction valve 13. A tension coil spring 21 has its respective endsconnected with valve 13 and an anchor bar 21a fixed with and extendingdiametrically across the upper end of the tube, to thereby urge valve 13onto its seat. Downward movement of the piston is limited by engagementbetween the flange of collar 18 and shoulder 8a. Since collar 18 isjournaled on tube 9b, the piston may rotate in the cylinder withoutunscrewing the spring.

The operation will be clear from the foregoing description. Piston 9 isdrawn downwardly in response to energization of the electromagnet andthus creates suction opening valve 13 and drawing a charge of fluid intothe upper end of the cylinder. When the piston starts its return orworking stroke under urge of spring 10, spring 21 closes valve 13, thetrapped fluid forces valve 9d open and the fluid is forced downwardly tooutlet or exhaust through passage 16a in sleeve 16.

The combined mass of the piston and parts carried thereby is relativelysmall so that the parts partaking of By this important feature the upperend take O-ring seals.

reciprocation do not necessarily have to be in resonance with thecurrent energizing the electromagnet. The electrical losses are small,so that it is not necessary that such losses be recovered in partthrough the gain usually required and attained by reciprication in timedrelation with the energizing current. Thus, as compared with prior artdevices, the invention provides a much more versatile instrument and awider range of pressures since the present pump is not restricted to thecomparatively small resonance range.

It will be noted that by detaching plate or support 12 from housing 1,the entire assembly including the support, cylinder and all partsmounted therewithin may be removed as a unit. Thereafter, by unscrewingthe cylinder from the support, the piston and valves are exposed forinspection and repair or replacement.

FIGURE 2 shows a modified form of the invention wherein the laminatedcore for the electromagnet comprises a lower E section 2' and an upper Esection 2". The upper section is inverted so that the longer arms are inend-to-end contact and conjointly define slots lined with spool 28 aboutwhich winding or solenoid 3' is disposed. Since the central arms of bothsections are shortened they define a space 6' between them.

The electromagnet thus formed is confined between top and bottom caps orplates 12' and 20, respectively. Top cap 12' has a central upper tubularprojection threaded at 12a to receive connections, not shown, from afluid supply, and a smaller downward tubular projection 12b sized for asmooth fit within and closing the upper end of cylinder 8. Thiscylinder, as shown, is a. plain thinwalled tube fitting a bore in thecentral arms of the core.

Lower cap 20 may be essentially a duplicate of cap 12', having adownward central tubular projection 20a threaded at 2012 for an outletor exhaust coupling, not shown, and an upper central projection 19smoothly fitting and closing the lower end of cylinder 8. As shown, bothprojections 12b and 19 are provided with channels to A sheath 29 'hasits ends threaded or otherwise secured to and about the caps, to enclosethe electromagnet.

Piston 9' has a smooth fit within cylinder 8. A central bore in thepiston is lined with a thin-walled tube 30 which extends from the lowerend of a counterbore 31 in the upper end of the piston, to a distancebelow the lower endthereof' The lower projecting end of tube 30 has acollar 18 journaled thereon and abutting the lower end of the piston. Inthe manner described previously for spring 10, FIGURE 1, a compressioncoil spring has its ends secured to collar 18' and projection 19 and isso constructed and arranged that in the position shown it issubstantially unstressed and thus will act to retard further upwardmotion of the piston from the position shown.

An 'apertured valve seat disc 32 is fixed over the top end of piston 9.A coil spring 33 within counterbore 31 acts between the shoulder formed"by the lower end of the counterbore and valve disc 34 to urge thelatter upwardly onto its seat on disc 32.

Lower projection 12b of upper cap 12' has been previously described. Thecentral bore of this projection has a lining 35 fixed therein. Thelining is flanged at its lower end to form a seat for suction valve 13whose stem 27 projects upwardly through a guide 26 extendingdiametrically across and in fixed relation with the upper end of lining35. A circular ledge 25 is fixed with the interior surface of the liningand forms an abutment for the lower end of a helical coil spring 24surrounding stem 27 and at its upper or smaller end abutting -a smalldisc fixed to stem 27. Valve 13' is thus urged upwardly into contactwith its seat on the flange of lining 35.

The operation of the modification of FIGURE 2 is basically like thatpreviously described for FIGURE 1 so that further explanation is deemedunnecessary. Likewise this modification has similar advantages of easeof servicing and repair and usefulness over a wider range of pressuresthan prior art devices.

As one of the many possible variations of the invention it iscontemplated that one or both of the outer arms of the E-shapedlaminated core may be shortened and each provided with an additionalpump unit which may be a duplicate of the one shown upon FIGURE 1 orthat depicted in FIGURE 2. Also, by making the central arm of the coreof sufficient size it may have two or more parallel axial bores orpassages in each of which a pump unit as in FIGURES 1 and 2 will bemounted. In the case of two such units, for example, the pistons maywork in opposite directions. That is to say, the cylinders will be inreversed positions and the working stroke of one piston will occursimultaneously with the suction stroke of the piston in the othercylinder. Also, the pump units may be connected for the pumping of fluidin series or in parallel, in the same direction of operation.

Numerous other modifications, and substitutions of equivalents, willoccur to those skilled in the art, after a study of the foregoingdisclosure. Hence the disclosure should be taken in an illustrativerather than a limiting sense; and it is my desire and intention toreserve all changes within the scope of the subjoined claims.

Although for convenience of description the terms downward, upward,etc., are used in the specification to describe the position of theparts as viewed upon the figures, it will be understood that theinvention may be used in any angular position with respect to thevertical and horizontal, or inverted from the positions shown.

Having now fully disclosed the invention, what I claim and desire tosecure by Letter Patent is:

1. In an electromagnetic piston pump, a cylinder having an inletconnection at its first end and an outlet connection at its second end,a piston of magnetic material slidably fitting said cylinder and havingan axial passageway for fluid, a suction valve in said inlet connectionand spring-urged to closed position, a pressure valve carried by saidpiston at the end thereof nearest said suction valve and spring-urged toclosed position, a spring in said cylinder between the second endthereof and said piston, and urging the latter toward said first end ofsaid cylinder, and electromagnetic means comprising a solenoidsurrounding said cylinder, said piston forming the armature for saidelectromagnet, said spring being a coil spring compressed by motion ofsaid piston in a suction stroke, and means positively connecting therespective ends of said spring with said piston and the second end ofsaid cylinder, said spring being substantially unstressed when saidpiston is at its normal position spaced from the first end of saidcylinder, and is under tension when the piston is displaced ztrom saidnormal position toward said first end whereby the motion of the pistonis checked during operation to limit movement to a predetermineddistance from said first end.

2. The pump of claim 1, said lastnamed means comprising a tube liningthe axial passageway in said piston and projecting therefrom toward saidspring, and a sleeve rotatably fittting about the projecting end of saidtube and threaded into the contiguous end of said spring.

3. The pump of claim 2, there being a circular shoulder internally ofsaid cylinder adjacent the second end thereof, said sleeve abutting saidshoulder tolimit reciprocation of said piston in a suction stroke.

4. The pump of claim 1, said electromagnetic means including a E-shapedcore having a central arm shorter than the end arms, said cylinderfitting an axial passage in said central arm, said solenoid being woundabout said central arm.

5. The pump of claim 1, said electromagnetic means including first andsecond E-shaped cores each having a shortened central arm, said coresbeing reversed with their end arms aligned in end-to-end relation todefine a space between the ends of said central arms, said cylinderextending through aligned axial passages in the central arms of saidcores.

6. In a pump of the type described, a cylinder, a piston of magneticmaterial having a longitudinal bore for passage of fluid and slidable insaid cylinder from a first position adjacent one end thereof, to asecond position adjacent the other end thereof, a compression coilspring in said cylinder, and means fixing the respective ends of saidspring to said piston and the other end of said cylinder said springbeing under compression when the piston is at one of said positions andunder tension when the piston is at the other of said positions wherebythe tensional spring limits movement of the piston to a predeterminedposition.

7. The pump of claim 6, and spring-pressed pressure valve means carriedby said piston at the fluid intake end thereof.

8. In an electromagnetically-operated piston pump, an E-shaped corehaving a central arm shorter than the outer arms of said core, asolenoid winding about said central arm, a yoke bridging the ends ofsaid outer arms, there being aligned central apertures in and throughsaid central arm and yoke, a cylinder fitting said apertures, a pistonof magnetic material reciprocably fitting said cylinder and having anaxial bore for passage of fluid, said bore being counterbored at itsfirst end, an apertured valve plate secured over said first end of saidpiston, a valve disk in said counterbore, spring means in saidcountenbore urging said disk :into contact with said plate to close theaperture therein, and a coil spring connected at its respective endswith the second end of said piston and the adjacent end of saidcylinder.

9. An electromagnetic piston pump comprising a support, a cylinderhaving its first end fixed to said support, there being 'an inletpassage in said support in axial alignment with said cylinder, a pistonof magnetic material slidably fitting said cylinder, and having alongitudinal bore for passage of fluid thereth-rough, spring-closedpressure valve means carried by said piston to close said bore at theend thereof nearest said first end of said cylinder, a spring-closedsuction valve over the opening of said passage into said cylinder, aspring in said cylinder between its second end and said piston, anE-shaped core of magnetizab le material having a shorter central arm,said cylinder fitting an axial passage in said central arm, a solenoidwinding about said central arm, and means detachably securing said coreand winding to said support.

10. The pump of claim 9, a tubular cage removab ly fitting the end ofsaid inlet passage opening into said cylinder and forming a circularsuction valve seat within said first end of said cylinder, a suctionvalve, and a spring connected at its respective end with said suctionvalve and a point in said cage remote from said piston. 11. In anelectromagnetic piston pump, first and second E-shaped cores each havinga shortened central arm, said cores being reversed and disposed withtheir end arms in aligned end-to-end contact, to define a space betweensaid central arms, a solenoid winding enclosing both said central armsand space, said central arms having aligned axial passages, a cylinderfitting said passages and traversing said space, first and second endcaps each having a projection fittting a respective end of saidcylinder, means connecting said caps together to embrace said cores andcylinder between them, there being an intake passageway through saidfirst cap and projection and an outlet passageway through said secondcap and projection,

, a piston of magnetic material slidably fitting said cylinder oppositesaid space, and having a longitudinal bore for fluid, an aperturedsuction valve sea-t plate secured to said piston over the bore thereinat the end adjacent said first cap, a first disk valve in said bore,spring means in said bore urging said disk valve into contact with saidplate to close the aperture therein, a tubular cage removab ly fitttingsaid intake passageway and forming an intake valve seat within the firstend of said cylinder, a stem slidable in and along said cage, a seconddisk valve fixed with one end of said stem and movable therewith to seaton said intake valve seat, a spring in said tubular cage and engagingsaid stem to urge the valve thereof onto said intake valve seat, a coilspring in said cylinder and having its ends positively connected withsaid piston and said projection of said second cap, said spring beingsubstantially unstressed when said piston is at the normal limit of itsstroke toward said first cap, with said valves in spaced parallelrelation.

12. An electromagnetic piston pump comprising, a support plate having aninlet passage therethrou-gh, a cylinder having a first end influid-tight communication with said passage, a piston of magneticmaterial slidably fitting said cylinder .and having a longitudinal :boretherethrough, apertured valve seat means secured over the end of saidpiston bore at the end nearest said passage, a valve in said here andspring-urged into position sealing the aperture in said valve seatmeans, said passage having a valve seat about its opening into saidcylinder, a disk valve, a valve spring having one end connected to saiddisk valve on the side thereof remote from said piston, and meansanchoring the other end of said valve spring at a point within saidpassage.

References Cited by the Examiner UNITED STATES PATENTS 2,488,384 [11/1949 Dickey et al. 2,801,591 8/1957 Parker 10353 X 3,194,162 7/1965Williams 103-53 X OTHER REFERENCES German application 1,101,960,February 1957.

ROBERT M. WALKER, Primary Examiner.

1. IN AN ELECTROMAGNETIC PISTON PUMP, A CYLINDER HAVING AN INLETCONNECTION AT ITS FIRST END AND AN OUTLET CONNECTION AT ITS SECOND END,A PISTON OF MAGNETIC MATERIAL SLIDABLY FITTING SAID CYLINDER AND HAVINGAN AXIAL PASSAGEWAY FOR FLUID, A SUCTION VALVE IN SAID INLET CONNECTIONAND SPRING-URGED TO CLOSED POSITION, A PRESSURE VALVE CARRIED BY SAIDPISTON AT THE END THEREOF NEAREAST SAID SUCTION VALVE AND SPRING-URGEDTO CLOSED POSITION, A SPRING IN SAID CYLINDER BETWEEN THE SECOND ENDTHEREOF AND SAID PISTON, AND URGING THE LATTER TOWARD SAID FIRST END OFSAID CYLINDER, AND ELECTROMAGNETIC MEANS COMPRISING A SOLENOIDSURROUNDING SAID CYLINDER, SAID PISTON FORMING THE ARMATURE FOR SAIDELECTROMAGNET, SAID SPRING BEING A COIL SPRING COMPRESSED BY MOTION OFSAID PISTON IN A SUCTION STROKE,